AD7761BSTZ-RL7

Overview

The AD7761BSTZ-RL7 is an 8-channel, simultaneous sampling sigma-delta analog-to-digital converter (ADC) housed in a 64-lead LQFP package. It provides a maximum output data rate of 256 kSPS per channel with a 110.8 kHz input bandwidth and 97.7 dB dynamic range. The device features three selectable power modes: fast mode dissipates 51.5 mW per channel at 256 kSPS; median mode operates at 128 kSPS with 27.5 mW per channel; and low power mode runs at 32 kSPS consuming 9.375 mW per channel. It supports decimation rates from ×32 to ×1024 and includes integrated precharge buffers for analog inputs and references.

Feature Summary

• Simultaneous sampling across eight channels with synchronized ac and dc signal conversion capabilities.
• Configurable digital filtering engine offering wideband linear phase response or low latency sinc5 filter options.
• Integrated analog input and reference precharge buffers designed to minimize input current and reduce glitches.
• Flexible power scaling architecture allowing optimization between noise performance, speed, and power dissipation.

Applications

• Data acquisition systems including USB, PXI, and Ethernet architectures
• Instrumentation and industrial control loops
• Audio testing and measurement equipment
• Vibration and asset condition monitoring
• High precision medical electroencephalogram (EEG), electromyography (EMG), and electrocardiogram (ECG)

Procurement Notes

Verify the specific ordering suffix RL7 confirms tape and reel packaging when sourcing this component. Confirm that the voltage supply requirements match your system design, specifically AVDD1 at 5 V and IOVDD compatibility with either 2.5 V to 3.3 V or 1.8 V logic levels. Ensure the 64-lead LQFP footprint aligns with your PCB layout constraints before finalizing procurement.

Selection Notes

Select the appropriate power mode based on the required balance between input bandwidth and power consumption. Fast mode is suitable for high-speed applications requiring 110.8 kHz bandwidth, while low power mode is ideal for battery-operated devices needing only 13.8 kHz bandwidth. Consider the decimation rate settings to optimize noise performance against the specific signal frequencies being measured.

Part Context

This component belongs to the AD7761 family of high-performance sigma-delta ADCs. It serves as a multi-channel solution for precision data acquisition, distinct from single-channel variants like the AD7768-1. The device integrates both the modulator and digital filter per channel, providing a complete signal chain for simultaneous sampling applications without requiring external processing for basic operation.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.

FAQ

What are the three operating power modes available for the AD7761?

The device offers Fast mode (256 kSPS, 110.8 kHz BW, 51.5 mW/channel), Median mode (128 kSPS, 55.4 kHz BW, 27.5 mW/channel), and Low Power mode (32 kSPS, 13.8 kHz BW, 9.375 mW/channel).

How does the AD7761 handle analog input current?

Each channel includes an embedded analog input precharge buffer that reduces the analog input current significantly compared to unbuffered operation, helping to minimize loading effects on the source.

What digital filter types are supported by this ADC?

The AD7761 supports a wideband low ripple filter with sharp roll-off for frequency domain measurements and a sinc5 filter which provides a low latency path for low bandwidth and low noise measurements.